-Brading Software Message Board
+--Forum: Mp3/Tag Studio Support and Bug Reports
+---Topic: Trim proglems started by calberga
Posted by: calberga on Feb. 26 2006,21:16
I've just be trying to cut a single mp3 file into four parts. I loaded the file into CoolEdit and located the desired cut-point, then I made four copies of the file and tried to trim them.
On some of the trim operations I got an error box "Invalid Pointer Operation", with a persistant "hourglass". BUT I can move the cursor (hourglass shaped) around, and continue doing things, which causes the hourglass to vanish. When I look, the trim was completed -- but see below.
After some, but not all, trims the red warning appears, that the VBR header is incorrect. The program seems to think that it is OK before I trim.
Further, most of the the trims are off by a few seconds.
So -- what shall I do, doctor? I don't think two aspirin and calling back in the morning will help.
PS, when I give a trim length such as 0:53.6 it isn't clear that the .6 is correctly interpreted. Of course, since the cut-points are off I can't be sure.
Posted by: Magnus Brading on Mar. 01 2006,23:26
It is very strange, some users get an error message like this in the trim tool, but when I get the sample file from them I have never (so far) been able to reproduce the problem.
The VBR header will practically always need to be updated after a cut, since it contains the length of the song (which has obviously been modified after a cut). So nothing strange there.
About inexact time, this has been observed before for some strange bitrate compositions. Have you tried the frame count mode?
Finally, your time format should be interpreted correctly.
Posted by: calberga on Mar. 02 2006,02:45
Could you explicate on the "frame count" method? I see nothing in the "help" under "Trim".
And, is there any way to corrolate time (which is what I read in CoolEdit) to frames, given that these are VBR files?
Am I missing a point here?
(Or, as a co-worker declared, very loudly, in a design meeting -- back around 1965 -- "Damn it, you're missing the wrong point!")
Posted by: Magnus Brading on Mar. 02 2006,09:46
In the trim tool, before performing the trim, select the option "Framecount mode" from the "Cut/info settings" box.
And yes, this is exactly what should be done in VBR files, since time is bound to the number of frames.
Posted by: calberga on Mar. 02 2006,16:07
But -- but -- but -- pardon the hole in my head. Exactly HOW is the time bound to the number of frames? Is there a simple formula? Sorry for being such a pest.
Posted by: Magnus Brading on Mar. 02 2006,16:33
One mp3 frame is approximately 0.026 seconds, at least for 44,100 Hz files.
But why do you want to know? In the the framecount mode, Mp3/Tag Studio takes care of these calculations for you.
Posted by: calberga on Mar. 02 2006,21:00
Just back from playing in the snow -- had to drive a bit in a snow-turning-to-ice storm -- not fun, but no problems.
I didn't realize that. I've switched to frame-count and gotten the trimming done, but still with some fiddling.
It seems that mp3/tag studio, even after repairing the VBR headers, disagrees with CoolEdit as to how long some of the files are. The differences are only a few seconds, but rather important.
So, I trimmed generously, then went back into CoolEdit and measured how much more I needed to remove and went back to M/T S and re-trimmed. At the 2 to 3 second scale they seemed to agree, however I now have files which CoolEdit thinks are 18:05 (the track length listed on the recording) but M/T S thinks are 18:03. 'Tis a puzzlement.
Glad to get it worked out, though.
Thanks for your help and your patience.
Posted by: calberga on Mar. 02 2006,21:01
PS, I still got the "pointer" error message, but only once this time.
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